The field of the invention pertains to devices that visualize the gastrointestinal (GI) tract from within the tract, in particular, devices such as endoscopes and enteroscopes.
Endoscopic technology has long since matured to visualize the entire colonic mucosa via colonoscopy and to visualize the esophagus, stomach and first 20 cm of the small intestine(duodenum). There is as of yet no fully satisfactory way of visualizing the full length of the small intestine. Currently, there are two types of endoscopes used to visualize the small intestine, the push endoscope and the Sonde (pull type) enteroscope. These two devices are very limited in their usefulness. The most efficacious way of inspecting the entire small bowel mucosa is to perform an intraoperative enteroscopy where the surgeon performs a laparotomy on the patient and actually moves the small intestine over the enteroscope. The enteroscope is driven by a gastroenterologist. Such a procedure is fully invasive and obviously an expensive and extreme measure to inspect the intestinal mucosa.
Adequate and efficacious visualization of the small intestine is the final frontier in the field of gastroenterology. Since the invention of the fiberoptic endoscope, there has been ceaseless improvement of upper (gastric) endoscopy and colonoscopy. Continual improvement has made inspection of the upper gastrointestinal mucosa (esophagus, stomach, and upper duodenal) a routine procedure that is highly effective and safe. Technology is now tending to plateau. For example, the current Olympus video endoscope has a scope diameter of 8 mm, and provides a high resolution magnified view of the stomach.
Similarly, colonoscopes are now highly maneuverable and quite small in diameter. Apparently it is no longer the goal of manufacturers to make smaller colonoscopes because it is believed that smaller, more flexible scopes will be more difficult to advance through the colon to the cecum.
Visualization of the small intestine, in contrast, has progressed little over the last ten years. Visualization of the small intestine is important especially in patients who have occult GI blood loss with no obvious source from the esophagus, stomach or colon. It is also important to examine the small intestine in patients with abdominal pain of unexplained origin and in patients with known diseases such as Crohn's disease or carcinoid syndrome. Barium small bowel follow-through is used most often to examine the small intestine, because of its ease and cost. However, this procedure rarely produces sufficient information for diagnoses. Physicians would usually prefer to visually inspect the small intestine mucosa if an adequate technique was available.
When a physician wishes to pursue investigation of the small intestine, the physician is left with the options of push enteroscopy, Sonde (pull type) enteroscopy or open intraoperative enteroscopy. Each of these technologies has failed to achieve widespread use because of the inherent drawbacks in each procedure.
The push enteroscope is similar in length and maneuverability to a colonoscope. However, trying to push a scope beyond the Ligament of Treitz is quite difficult because of the multiple turns of the small bowel. At best most push enteroscopes can visualize less than half of the small intestine.
The Sonde enteroscope is a narrow device about 300 cm long. The Sonde device is inserted into the stomach and then is allowed to advance through the small intestine by peristalsis. Approximately six hours are required to pass this scope through the entire length of the small intestine because of the resistance to movement. The device allows visualization of the entire small intestine when successfully passed, however, the great length of time for the procedure is a definite drawback.
The intraoperative enteroscope procedure is done when a diagnosis of small bowel pathology is sought and less invasive tests have been non-diagnostic. The procedure requires a laparotomy by a surgeon in combination with small bowel enteroscopic viewing by a gastroenterologist working in concert to advance the scope over the entire length of the small intestine. It is obviously much more risky to the patient and involves high costs and intensive use of resources.
A variety of experimental devices have been studied. These devices fall into two broad categories. The first group comprise electromechanical devices that are bendable or articulated over their length and are advanced by force produced at their proximal ends outside of the patient. The second group comprise devices that crawl by means of traction producing apparatus acting against the wall of the small intestine. The traction devices may exacerbate the potential damage to the wall of the small intestine beyond the potential damage of existing commercial enteroscopes.
Because of the failure to develop adequate means of evaluating the small intestine, patients frequently undergo a step-wise approach of undergoing one procedure followed by another, each with increasing invasiveness, risks and costs. If a device could be developed that would easily, efficiently and effectively visualize the entire length of the small intestine, this would be a dramatic step forward in the practice of medicine. To overcome the shortfalls of the existing enteroscopes and eliminate the difficulties of the crawling mechanisms, a new mechanism which enables a device to be easily delivered through the small intestine and allow access of light and power to the distal end is disclosed below.